Plug-switch.



J. I. AYER'.

PLUG s-vsrI'JtcH.` AIPLIOATION FILED AUG. 12,1904.

Awww GRAHAM oo. HmuLm-xocMmFM WASHINGTON. lu'.

UNITED s TATEs PATENT oEEioE.

JAMES I. AYER, OFCAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO SIM- PLEX ELECTRIC HEATING COMPANY. OF CAMBRIDGE, MASSACHU- SETTS, A CORPORATIONOI?` MASSACHUSETTS. Y

PLUG-SWITCH.

Specication of Letters Patent.

Patented Aug. 1, 1 t 05.

Application filed August 1.2, 1904. Serial No. 220,515.

T0 all whom 7115 may concern:

Be it known that 1, J AMES I. AYER, a citizen of the United States, residing at Cambridge, in the county of Middlesex and State of Massaohusetts, have invented an Improvementin Plug-Switches,of which the following description, in'connection with the accompanying cuit cannot be made by the contact of the plugterminals with the cover of the receptacle.

In the best form of my invention now known to me I make the plug-receptacle, which has the usual receptacle-terminals therein, with a cover carrying bushings of insulating material, the hole'through the bushings constituting the openings through which the plug-terminals are inserted when a switch is to be closed.

Referring to the drawings, Figure 1 is a section through my improved switch, the section through the receptacle part being taken on the line Eig. 2. Fig. 2 is a top plan view of the receptacle. Fig. 3 is a section through the receptacleon the line yy. Fig. 4 is a bottom plan view of the switch-plug. Eig. 5 shows the Linder plate of the cover removed, and Eig. 6 is a modification.

The body of the plug-receptacle is designated by 3, and it may be of any suitable or usual material, but preferably of porcelain or some other insulating material. The receptacle contains the receptacle-terminals 4, which may be of any suitable character and each of which is herein illustrated as a pair of spring contact-plates, between which the corresponding plug-terminal is adapted' to be inserted. f

, Each terminal 4 may be secured to t-he receptacle in any appropriate way, andeach will have electrically connected thereto a wir 5, forming part of the circuit.

The form of receptacle shown is-divided byy The receptacle is lprovided with a cover having openings therethrough whichare situated over the terminals 4 and through which the plug-terminals 12 are inserted. These plug-terminals are secured to a suitable plug or body 13, and each are connected to one of the wires 14.

The form of receptacle herein shown is what I have termed a flush receptaclethat is, it is made to be set into a wall or other supporting material 140, so thatA the cover thereof will come iiush with said wall.

The cover of the-receptacle is of metal, as

is usual in this class of devices, and to prevent a short circuit from being formed when the plug is withdrawn or inserted by the accidental engagement of the plug-terminals with said cover I have devised the following novel construction. The cover comprises the under plate 16, which is shown removed in Fig. 5, and the face-plate 18, which is superimposed on the lower plate 16 when the parts are assembled. The plate 16 is provided with bushing-receiving slots 17, said slots both preferably being widened at their inner ends to facilitate the insertion of the insulatingbushings.

15 designates bushings of any suitable insulating material-such as porcelain, hard rubber, ctc-said bushings having openings 11 therethrough for the reception of the plugterminals. Each bushing is provided at oppositesides with a groove 20, in which the edge of the slot 17 in the plate 16 is adapted to fit. The bushings are placed in the slot from the central portion of the plate where the slot is wide enough to permit the bushing to be inserted. The face-plate`18 is provided with openings of a size to receive the bushings 15, and said face-plate is detachably secured to the lower plate in any suitable way, as by screws 1.9. In assembling the parts the receptacle 3 is first placed in the recess in the wall in which it is received and the lower plate 16-put in place and there retainedby suitable screws 41. The bushings 15 are then inserted in the slots 17 from the wide ends thereof, the edges of the slots being received `in the grooves 2O in said bushings, 'and thus After the holding said bushings in place. bushings are properly located over the receptacle-terminals 4 the face-plate 18 is put in plate just lit the bushings, said face-plate holds the bushings from movement parallel to the top of the receptacle, and the lower plate 16 by entering the groove 20 of the bushings holds them from being pulled out of the receptacle.

From the above it will be seen that the bushings are detachably secured to the receptacle in such a way that they may be readily removed should they be broken or injured and new bushings put in place.

Another way of practicing my invention is shown in Fig. 6, wherein the two openings 1l for the plug-terminals are both formed in a single insulating member Q3, the latter being held between the two parts 24 of the receptaele-cover. In this form of my invention I also preferably provide the insulating member 23 with grooves in which the edges of the plates 24: are seated.

The advantage of the construction herein described is that it prevents the possibility of a short circuit being created by any of the metallic parts of the receptacle-cover and is certain to extinguish any arc at the points of the receptacle -terminals when the plug, is withdrawn, no matter how carelessly this may be done.

Another advantage is that the receptaclefront is completely closed except for the narrow openings 1l, thereby preventing the switch from being tampered with and protecting the contacts 4 from dust and dirt.

I desire to call attention to the fact that in both forms of my invention the insulatingbushings are of considerable size compared -with the openings 11 for the plug-terminals.y

This is important, as it makes the device especially adapted for use in circuits of high potential and large current.

Another feature which I regard of. importance is the fact that the bushings are detachably secured to the cover, as this enables me to use porcelain bushings and also to replace a bushing in case one breaks or becomes damaged.

While I have shown two ways of embodying my invention, I do not wish to be limited thereto, as the arrangement and shape ofthe parts may be varied without departing from the invention.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In a plug-switch, a plug-receptacle having receptacle-terminals, a cover for said receptacles, said cover comprising two separate plates having insulating-bushings carried by one plate and projecting through the other plate, the apertures in said bushings being situatedover the receptacle terminals and constitutingopenings to receive the plug-terminals.

2.' In a plug-switch, a plug-receptacle having receptacle-terminals, a cover for said rcceptacle, said cover comprising an under plate and a face-plate, insulating-bushings extending through both plates, said bushings being situated over the receptacle-terminals and cach being held from movement toward and from the corresponding terminals by one plate and from movement laterally by the other plate.

3. In a plug-switch, a plug-receptacle having receptacle-terminals, a cover for said receptacle, said cover comprising an under plate and a face-plate detachably secured together, insulating-bushings carried b v the under plate and projecting through the face-plate, the apertures in said bushings being situated over the receptacle terminals and constituting openings to receive the plug-terminals.

4. In a plug-switch, a plug-receptacle having receptacle-terminals, a cover for said receptacle, said cover comprising an under plate and a face-plate detachably secured together, detachable insulating-bushings carried by the under plate and projecting through the faceplate, the apertures in said bushings being situated over the receptacle-terminals and constituting openings to receive the plug-terminals.

5. In a plug-switch, a plug-recel'itacle having receptacle-terminals, a cover for said rcceptacle, said cover comprising an under plate having bushing-receiving slots and a face-plate having openings, and insulating-bushings occupying the slots of the under plate and projecting through the openings of the face-plate.

6. In a plug-switch, a plug-receptacle having receptacle-terminals, a cover for said receptacle, said cover comprising an under plate having bushing-receiving slots and a face-plate having openings, and detachable insulatingbushings occupying the slots of the under plate and projecting through the openings of the face-plate.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JAS. I. AYER..

Witnesses:

ELIZABETH M. CoNLIN, ETI-Inn BRADSHAW. 

